Safety attachment.



T. STOBS.

SAFETY ATTACHMENT. APPLICATION FILED APR. 14. 1916.

2 SHEETS-SHEET 1- Patented Feb/19, 1918.

T. STOBS.

SAFETY ATTACHMENT.

APPLICATION FILED APR.14. 191s.

Patented Feb. 19, 1918.

v 2 SHEETS-SHEET 2.

THUMB-S STOBS, 0F MAYWOOE, HALINOIS.

SAFETY .AT'I'A J 1,257,148, Specification of Letters 2mm.

, M'mlcation filed April 14, 191a Serial No. 91,015.

To all whom it may concern:

Be it known that I, Tnoms STo'Bs, a citizen of the. United States, and a resident of Maywood, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Safety Attachments; and I' do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention relates to improvements in safety attachments more especially intended for intermittently operating machines such as die resses, punch presses, paper cutters,

drop orging machines and the like and consists of the matters hereinafter described and more particularly pointed out in the appended claims.

The safety attachment is of the kind which generally includes two arms or handles, that are required to be manipulated in order to operatively connect the .press to its power driving member so that both hands are necessary to cause thepress to operate. With both hands engaged, it is impossible for the operator to get either hand caughtin the press.

The present invention is' directed to a novel and improved form of this sort of safety attachment. One of the primary objects of the" device in theembodiment of the invention shown here, is to make it impossible for the workman to start the machine without using the safety appliance exactly as it is designed to be used. The attachment is thus made foolproof, so to speak, and the operator cannot employ other means than his two hands to manipulate the safety attachment. This and other advantages will appear as I proceed with my specification.

Referring now to the drawings Figure 1 is a view representing aside elevation of the press provided with my improved safety attachment, the elevation being as looked at from the right hand side of the press. I

Fig. 2 is a view representing a front elevation of the press.

Fig. 3 is a view representing a side elevation of the press as it appears when viewed from the left side.

Fig. 4 is a view representing a transverse section through the press in aplane indicated by the line 44 of Fig. 1.

may be operatively Figs. 5, 6 and 7 are detail, side elevational news of the safety attachment with the press omitted, the several views showing the parts in the successive positions which they occupy when the attachment is operated.

Referring now to that embodiment of my invention illustrated in the drawings :10 mdicates a machine of the kind described of any usual construction. The press in thls case is the familiar die or punch press. The'press shown is of the tilting bed and comprises a fixed basell and a tilting body 12, which may be swung upon the base in a familiar manner toincline the bed plate 13. 14 indicates the plunger, which is operatively connected to a shaft 15, adapted to be driven by a pulley 16. The pulley 16 is loose on the shaft but connected thereto by tripping a sprmg-controlled clutch of the usual kind contained in the hub 16 of the pulley. These parts are all of familiar ponstruction and need no'further descrip- The clutch is normally held in such a position as to prevent operative connection of the pulley 16 to the'shaft 15 by means of a spring-controlled rod 17. 'Said rod has sliding bearing in lugs 1818 formed on a plate 19 fixed to the side of the press and a suitably mounted coiled spring 20 mounted on the rod between said lugs acts to hold said rod in an elevated positlon in. engagement with the tripping mechanism of the clutch so as to make said clutch inoperative.

The safety appliance includes a right hand arm 21 and a left hand arm 22; These arms are placed on opposite sides of the press and as s tilting body of the press. Said arms are coupled together by a horizontal, transverse, rock shaft 23 mounted in the tilting press body, back of the plane in which the plunger reciprocates, and by means of a short crank arm 24. The arm 22 is fixed to the rock shaft 23. The crank arm 24: is also fixed to the shaft 23 and is pivotally connected to the right hand arm 21.

The arm 21 has a goose-neck 21 at its rear end, which is pivoted to the crank arm 24 which stands m an upright position. The arm 21 normally rests at a point intermediate its ends upon a stop 25 fixed to the side face of the swinging body of the press. This stop normally prevents the arm 21 Patented net. as, rare.

kind having a own herein, are mounted on the y from being moved. The arm 21 is connected to the tripping rod 17 in such man ner that when the said arm 21 is depressed, it will pifll down the rod 17 against the "action of the spring 20. This connection consists of an arm 26 pivoted to the press body on a pin 27 located above the crank arm 2i; of a link 28 which is pivotally .connectedlo the forward end of said arm 26 and is also directly connected to the rod 17; and of a link 29 which is pivotally connected to the arm 26 at a point intermediate its ends and is pivotally connected to the arm 21 at a point forward of the goose-neck 21' and to the rear of the stop 25. Thus,

when the arm 21 1S swung downwardly- .upon its pivotal connection with. the crank arm 24, as will presently be described, it, through the link 29, swings the arm 26 downwardly which link 28 and the the spring 20.

On the left hand side of the machine, there is associated with the arm 22 a mechanism connected with the drive shaft for positively returning the attachment to its position after each operation of, the press. This mechanism is as follows :a cam 30 is fixed on the shaft 15 in the vertical plane in which the arm 22 operates. 31 indicates an arm pivoted to the side of the press body to the rear of the shaft 15 at 32 and operatively engaged at its forward end 33 with the cam 30, an antifriction roller 33 being carried at said forward end with direct engagement with the cam. 34 indicates a rod which connects the arm 31 with the arm 22. Said rod has a fork 35 at its bottom endwhich embraces the arm 22 and which carries a pin 36 that engages in a vertical slot 37 in the arm 22.

rod 17 against the action of A coiled spring 38 connecting the arm 31 to a fixed part on the frame acts to hold the anti-friction" roller 33 in positive engage- .ment with the cam 30. The parts normally stand in the position indicated in Figs. 1, 2 and 3. v v

The parts are designed to act as follows:When the press is to be started, the

left hand arm 22' is depressed This is made possible by reason of the fact that the pin 36, as the parts are designed, normally stands in a position near the bottom of the slot 37 in the arm 22. The movement downward of the arm 22 rocks the shaft 23 forwardly and the crank arm .24 in the same direction so that the arm 21 is bodily moved forward, the'parts being brought into the position shown in Fig. 5. The arm 21 is provided on its under side with a notch 40, which is so placed in the arm that when the parts are in the position indicated in Fig. 5, after the movement above described, said notch will be in a position in line with the stop 25, such that the arm 21 with its pivotal in turn pulls down theconnection with the arm 24 moved for wardly as described, may be swung downwardly without engaging the stop until it has moved far enough to pull down the arm 26 and actuate the tripping member, as shown in .Fig. 6. This movement trips the clutch in a familiar manner and the pulley 16 is operatively connected with the shaft. As the shaft rotates and producesa reciprocation of the press, the cam 30 rotates in the direction indicated by the arrow in Figs. 3, 5, 6 and 7, and the operation is such that when the shaft 15 is approaching a completerevolution, the arm 31 begins to rise. In this movement it lifts the pin 36 vwhich is now engaged with the top of the notch and thus lifts the arm 22 so that finally at the end of the revolution of the shaft, the arm 22 has been raised to its original position. In this movement the rock shaft 23 is-turned backwardly so ,as to draw the arm 21 toward the rear, thus bringing said arm again into sup orting engagement with thestop as in the st position of the parts, so that the spring-controlled tripping member 17 is again returned in the path of the trip of the clutch and the pulley 16 is operatively disconnected from the shaft 15.

From the foregoing description it is apparent that the workman is unable to tie the" arm 22 down and thus arrange the attachment in such manner that he can operate it with one hand. The attachment operates .to actually effect the disconnection of the driving pulley from the shaft after each operation, at the same time'returnin the parts of the attachment to their origina positions, and it is thus necessary for the operator to use both hands when he desires to start the press.

The many advantages of my invention wliill be manifest to those familiar with the a I claim as my invention:- Y

1. A safety appliance of the kind described, comprising in combination with a machine, a tripping member for startin said machine, a rock shaft, an arm adapte to rock said shaft, a short crank arm at the other end of said shaft and adapted to be operated thereby, a third arm pivotally connected with said crank arm, means connecting said third arm with said tripping member, a stop to prevent said third arm from operating said tripping member, said third arm being provided with a notch'which in a certain position of the parts will be in line with said stop, and means for returning said parts to their initial position after each op-' eration of the machine.

2. A safety appliance of the kind described, comprising in combination with a machine, a spring-controlled tripping memmeans an arm fixed to one end of said shaft, a short crank arm fixed in an upright position to the other end of said shaft, a third arm pivotscribed, comprising in combination with the drive shaft of a machine and the pulley and clutch thereon, a tripping member for starting said machine, a rock shaft, an arm fixed to one end of said shaft, a cam on said drive shaft, means intermediate said cam and said arm for returning said arm to its initial position after it has been depressed and when the shaft has made. a rotation, a short crank arm fixed in an upright position at the other end' of said rock shaft, a third arm pivotally connected to said crank arm, a stop adapted to normally prevent the depression of said third arm, said third arm being provided with a notch adapted to be brought into alinement with said stop when said crank arm has been shifted by the operation of the first-named arm, and means operatively connecting said third arm with said tripping member.

4. A safety appliance of the kind described, comprising in combination with the drive shaft of a machine and the pulley and clutch thereon, a tripping member for starting said machine, a rock shaft, an arm fixed to one end of said shaft, a cam on said drive shaft, means intermediate said cam and said arm for returning said arm to its initial position after it has been depressed and when the shaft has made a rotation, a short crank arm fixed in anupright position at the other end of said rock shaft, a third arm having a goose-neck pivotally connected to said crank arm, a stop adapted to normally prevent the depression of said third arm, said third arm being provided with a notch adapted to be brought into alinement with said stop when said crank arm has been shifted by the operation of the first-named arm, a fourth arm pivoted above said third named arm and connected to said tripping member, and a link connecting said fourth arm to said third arm at a point intermediate said notch and its connection with said crank arm. n

In testimony that I claim the foregoing as my invention 1 afiix my signature in the presence of two-witnesses, this 11th. day of' April, A. D, 1916. v

THOS STOBS.

Witnesses: 11H. Anrnnns, KARL W. Donn. 

